Forensic Artifacts of the Flareget Download Manager
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Forensic Artifacts of the flareGet Download Manager Prachi Goel1 and Babu M. Mehtre2(&) 1 School of Computer and Information Sciences, University of Hyderabad, Hyderabad, India [email protected] 2 Institute for Development and Research in Banking Technology (IDRBT) Established by Reserve Bank of India, Hyderabad, India [email protected] Abstract. There is an increasing interest in finding artifacts (digital evidence) created by various software tools. flareGet is an advanced multi-threaded and multi-segment download manager for Linux. This is the only download manager for Linux that integrates with almost all the browsers. In this paper, we examine (from a digital forensics angle) the artifacts created by flareGet for Linux, specifically on Ubuntu 12.04 distribution. The flareGet artifacts include down- load path, URL address, settings of flareGet, date and time of the activity per- formed, the encryption technique used by flareGet, etc. This is useful for the digital forensic investigator to search and interpret the artifacts created or left in the process of using flareGet. Keywords: Artifacts Á Digital forensics Á Investigation Á flareGet 1 Introduction There is an increasing interest in finding artifacts (digital evidence) created by various software tools. There are a number of software tools which have been examined for artifacts on Windows and Linux platform. Relatively, the number of such tools examined for artifacts on Windows platform is more than those on Linux platform. flareGet is a native Linux application written in C++, using the Qt framework. For installing flareGet, the system should meet the following minimum dependencies: 1. Qt libraries with version >=4.8.1 2. glibc (C library) with version >=2.13. flareGet is a full featured, advanced, multi-threaded, multi-segment download manager and accelerator on Linux [1]. It supports all 32 and 64 bit ‘Debian’ and ‘Red Hat Package Manager’-based Linux distributions. flareGet is proprietary software however; it is also available freely with limited features. The following features are not present in the freely available flareGet version 1.4-7: 1. Up to 16 parallel connections per download. 2. Browser Integration with all the browsers. © Institute for Computer Sciences, Social Informatics and Telecommunications Engineering 2014 P. Gladyshev et al. (Eds.): ICDF2C 2013, LNICST 132, pp. 30–38, 2014. DOI: 10.1007/978-3-319-14289-0_3 Forensic Artifacts of the flareGet Download Manager 31 3. Support for download speed limits. 4. Support for auto-refreshing of URL and cookies. Freely available, flareGet can support up-to 8 parallel connections per download and provides the integration with Mozilla Firefox via FlashGot (a third party add-on). flareGet supports HTTP, HTTPS and FTP for downloading the files from Internet. It also supports Meta links. It uses a robust dynamic file segmentation algorithm which splits the download into segments to accelerate the process of downloading. In addition to dynamic file segmentation, it uses HTTP-pipelining in which multiple requests are sent on a single TCP connection without waiting for the corresponding responses. This further accelerates each segment up to six times. It uses intelligent file management to automatically categorize the downloaded files based on their extensions. The down- loaded files are grouped into different folders as per their categories. This paper focuses on the artifacts created in the process of using flareGet (freely available version 1.4-7) on Linux (Ubuntu 12.04 distribution). Even though the examination is done by using the free version of flareGet, the same type of artifacts are applicable to professional flareGet (because the features which are not available in the free version would not affect the artifacts created by flareGet). It is found that flareGet creates the artifacts in the location: ‘/home/< user >/.config’ with different folder names. The important folders created by flareGet from the forensics point of view are discussed in the following sections. All the traces created by flareGet are traced by using Strace (a debugging utility for Linux). The GUI of the flareGet download manager is shown in Fig. 1. The Left Panel of flareGet contains two main tabs: ‘All Downloads’ and ‘Finished’. Under the ‘All Downloads’ tab there are various status tabs which include Completed, Running, Paused, Failed and Cancelled. Under the ‘Finished’ tab there are various categories tab which include Compressed, Application, Documents, Videos, Audio, Images and Others. The Right Panel displays the information of the corresponding tab on the left panel when clicked by the user. For example, in Fig. 1, the right panel shows the information of all the files including their states like completed, running, paused, failed and cancelled, shown when the ‘All Downloads’ tab on left panel gets clicked. Fig. 1. The GUI of flareGet. 32 P. Goel and B.M. Mehtre This paper is organized into 5 sections. The first section gives a brief introduction of the flareGet. The second section discusses the related work done by others. The third section details the artifacts of flareGet in five sub-sections. Sections 3.1, 3.2 and 3.3 describe from where the forensic investigator can find the downloaded/downloading files, proxy settings and paused file information. Section 3.4 describes from where the forensic investigator can find the information about websites requiring authentication during the download process, and it also describes the encryption technique used by flareGet to store the user’s passwords for these websites. Section 3.5 shows the installation and un-installation artifacts of the flareGet. The summary of flareGet arti- facts is given in Sect. 4. Finally the paper concludes in Sect. 5. 2 Related Work Numerous researchers have worked to find the artifacts left behind by different software applications from the digital forensics perspective. In the literature there are many papers for detecting software application artifacts on the Windows platform but less research has been done to find software application artifacts on the various Linux platforms. The Windows Registry provides essential information from forensics point of view [2]. Vivienne Mee et al. [3] examined the use of the Windows Registry as a source of forensic evidence in digital investigations, especially related to Internet usage. Bit Torrent is a peer-to-peer file sharing protocol used for distributing large amounts of data. It has been seen that usage of Bit Torrent client application leaves the traces in the registry [4]. Increase of the Gnutella network (peer-peer network) usage lead researchers to find the artifacts left behind after the use of Limewire [5] and FrostWire [6] software tools. Geoffrey Fellows [7] presented WinRAR temporary folder artifacts which provide the essential evidence to the investigator to prove which files were viewed or extracted using WinRAR program. Muhammad Yasin et al. [8, 9, 10] analyzed the ‘Download Accelerator Plus’, ‘Free Download Manager’ and ‘Internet Download Manager’ for collection of digital forensic artifacts. Many Instant messenger software applications have been examined which provide exchange of text messages in real-time. These include Yahoo Messenger 7.0 [11], Trillian basic 3.x [12], MSN Messenger 7.5 [13], AOL Instant Messenger 5.5 [14], Windows Live Messenger 8.0 [15] and Pidgin Messenger 2.0 [16]. Steganography, whole disk encryption and private browsing are some of the challenging areas for forensics investigators. Rachel Zax et al. [17] presented the traces left behind after a number of freely available steganography tools were installed, run, and uninstalled. Sungsu Lim et al. [18] investigated the installation, runtime, and deletion behaviors of virtual disk encryption tools in a Windows XP SP3 environment. Huwida Said et al. [19] examined the artifacts left by conducting Web browsing privacy mode sessions in three widely used Web browsers (Firefox, Google Chrome and Internet Explorer), and analyzed the effectiveness of this tool in each Web browser. Forensic Artifacts of the flareGet Download Manager 33 3 flareGet Artifacts 3.1 Downloaded Files Information The important question during investigation of a download manger is what are the files that were downloaded or are still being downloaded by the user. There are two ways to find this information. The first way is to look at flareGet.conf file which is located in the directory ‘/home/<user>/.config/flareGet_ALLDOWN’.Thisfile contains the entire downloaded and downloading file information. Figure 2 is showing the portion offlareGet.conffile. The CurrLength in this file indicates the total number of files which is the count of downloaded, downloading, cancelled, failed, paused and queued, provided the user has selected to remember the finished, cancelled and failed downloads in settings page of flareGet. If the user has not selected to remember the finished, cancelled and failed downloads then the CurrLength indicates the total number offiles which are paused or queued. Even if the user has unchecked to remember the finished, cancelled and failed downloads then the inves- tigator can also find this information in the file ‘flareGet.conf’, provided it is not over- written by another file information because flareGet overwrites the whole flareGet.conf file at the time of exit. The same is applicable to the files which get deleted by the user from flareGet, i.e., the file information remains until overwritten by the flareGet. Each down- loaded file information record starts with an integer. For example, in Fig. 2 the file having the name ‘TrueBackLin.zip’ indicated by ‘fname’ started with integer ‘0’. All the attributes of this file start with integer ‘0’. Similarly the next file attribute starts with integer ‘1’ and so on. The important attributes from the forensic point of view are explained below: furl: shows where the downloaded file is stored. fsize: shows the size of the downloaded file in string format. durl: shows the web address from where the file gets downloaded. flocation: shows where the downloaded file gets stored.